JPS61173469A - Fuel cell - Google Patents

Abstract

PURPOSE:To ensure the uniform flow of gas even when a resin film is peeled off by covering the metal inner surface of a manifold with a heat resistant, chemical resistant resin film and mounting a resin film holder between the resin film and a cell main body. CONSTITUTION:The inner surface of a manifold 3, 4, 6, 7 made of metal is covered with a heat resistant, chemical resistant resin film 8, and a net-like resin film holder 9 is mounted inside the resin film 8. In a fuel cell having such manifold, even when the resin film 8 is peeled off from the manifold 3, 4, 6, 7, the resin film 8 is supported by the holder 9, and the gas supply to a cell main body 1 is surely maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fuel cell that uses hydrogen as a fuel and oxygen or air as an oxidizing agent, and particularly relates to a fuel cell that is designed to have a long service life.

[Technical background of the invention and its problems] In recent years, there have been great expectations for the practical application of fuel cells as a power generation device with low pollution factors and high energy conversion efficiency, and the development of fuel cells has been strongly promoted by the public and private sectors. It's coming. This fuel cell usually has a pair of porous electrodes sandwiching an electrolyte-impregnated matrix, a fuel such as hydrogen is brought into contact with the back of one electrode, and an oxidizing agent such as oxygen is brought into contact with the back of the other electrode. The device is designed to extract electrical energy from between the electrodes using the electrochemical reaction that occurs at this time, and as long as the fuel and oxidizer are supplied, electrical energy is extracted with high conversion efficiency. It is something that can be done.

FIG. 6 is an exploded perspective view showing an example of the configuration of a conventional fuel cell. In the figure, a fuel cell main body (hereinafter simply referred to as the cell main body) 1 is sandwiched between upper and lower reinforcing members 2, and a fuel inlet manifold 3 and a fuel outlet manifold 4 are provided with sealing material on one side facing the cell main body 1. 5, and are configured to supply and discharge fuel to and from the battery body 1. Further, on the other side facing the battery body 1, an air inlet manifold 6 and an air outlet manifold 7 are provided through a sealing material, respectively, to supply and discharge air to and from the battery body 1. . Furthermore, these manifolds 3.degree., 4.6.7 are operated while being kept airtight and housed entirely in a closed container (not shown) filled with an inert gas such as nitrogen.

By the way, the manifold in the above-mentioned fuel cell not only needs to have a structure that can withstand internal and external pressure fluctuations, but also needs to be used at an operating temperature of about 200°C, so that the fuel cell The manifold structural material may corrode due to evaporation or scattering of phosphoric acid, which is the electrolyte.

Recently, since there are few materials that have sufficient resistance to high-temperature phosphoric acid, a method has been adopted that uses metal for a pressure-resistant structure and coats its inner surface with fluorine-based resin (Teflon). There is. However, in this type of resin, although the resin itself has strong heat resistance and drug resistance, there is a problem in that the coating easily peels off. This is because there is no brimer that can be used at 200℃ for adhesion of coating materials, and the coefficient of linear expansion is 11.8x that of iron.
10-'(f/'C) vs. 10X10 in TFE
It is different from -5 by one order of magnitude, and is easily peeled off due to temperature changes due to temperature rises and falls during plant startup and shutdown.Furthermore, due to the gas permeability of the resin itself, gas that reaches and stagnates between the manifold and the resin will cause the plant to shut down. This is due to the fact that the manifold sometimes expands due to pressure drop and the coating peels off from the manifold.

Such peeling progresses gradually as the plant is repeatedly started and stopped, and as shown in the cross-sectional view in Figure 7, it leans against or hangs down on the battery body, obstructing the flow of gas to the battery. .

When the flow of gas to this battery is obstructed, a polarity reversal phenomenon occurs in the parts of the battery where gas does not flow, and the battery voltage immediately drops.If the plant continues to operate, the polarity reversal phenomenon will occur. A problem arises in that the damaged battery is damaged to the point where it cannot be reused, and furthermore, the stacked batteries above and below it are damaged one after another. Therefore, if the coating peels off and the battery voltage drops, it is necessary to stop the plant operation. However, in this case, there are various difficulties in removing the peeled off coating, and the plant is shut down for a long period of time.

The above-mentioned situation has a large impact on the power system, and the reliability of the fuel cell as a power generation facility is significantly reduced.

[Purpose of the Invention] The present invention was made to solve the above-mentioned problems, and its purpose is to prevent the resin film from leaning against or hanging down on the battery body even if it peels off, thereby preventing gas from flowing. The object of the present invention is to provide a fuel cell that can ensure uniform flow, perform continuous operation over a long period of time, and improve reliability as a power generation facility.

[Summary of the Invention] In order to achieve the above object, in the fuel cell of the present invention, the inner surface of a metal material as a manifold structural material is wrapped in a heat-resistant and chemical-resistant resin film, and there is a gap between the resin film and the battery body. The structure is such that a resin film holder is attached to the holder, so that even if the resin film is peeled off, a uniform flow of gas is ensured and good power generation can be performed.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing an example of the configuration of a manifold applied to the present invention, and the same parts as in FIGS. 6 and 7 are designated by the same reference numerals. In the figure, the inner surface of a manifold 3, 4.6° 7 made of metal material is wrapped in a heat-resistant and drug-resistant resin film 8, and a mesh-like resin film holder 9 is attached to the inside of this resin film 8. There is.

FIG. 2 shows a view taken along the line A-A' in FIG. In the figure, the resin film 8 is located between the holder 9 and the manifolds 3, 4, 6.7. This holding body 9 is
It is not necessary to press the resin film 8 against the manifold 3.4.6.7, and there may be a gap. Furthermore, even if the holder 9 comes into contact with the resin film 8, there is a gap between the horizontal bar of the holder 9 and the resin film 8, and the phosphoric acid condensed on the resin film 8 will be transferred to the horizontal bar of the holder 9. It flows downward without being retained and is discharged outside the manifold to prevent corrosion of the manifold.

Roughly speaking, horizontal bars are provided at the top and bottom of the holder 9 so that the holder 9 can always maintain a vertical posture without leaning against the battery body 1. However, the holder 9 is configured not to come into direct contact with the battery body 1, so as to prevent an electrical short circuit between the upper and lower parts of the battery body 1.

FIG. 3 shows a cross-sectional view of the holder 9, which is constructed by housing a metal rod 11 in a resin tube 10 and enclosing both ends thereof. FIG. 4 shows an example in which a flat metal rod 11 is enclosed in a resin tube 1o.

On the other hand, in the above, it is preferable to use a resin film 8 that has been previously formed so as to match the inner surface of the manifold 3.4.6.7. Furthermore, usable resin film 8 and resin tube 10 include TFE, PFA, PEP, etc. as heat-resistant and chemical-resistant fluororesins.

In this case, if the manifold structure becomes complicated, TFE
However, it is difficult to process and requires welding, gluing, etc.
Since PFA, FEP, etc. have fluidity when heated, a free shape can be obtained using a film. Furthermore, TFE,
PFA can withstand continuous use temperatures of 260°C and FEP at 200°C. On the other hand, the thickness of the film is 0.2~
Approximately 0.5m is desirable.

Further, on the premise of peeling, a thick coating of emulsion or powder may be applied to obtain a film of a constant thickness.

In a fuel cell equipped with a manifold having such a configuration, even if the resin film 8 is peeled off from the manifold 3.4°6.7, the resin film 8 only leans against the holder 9, preventing gas flow to the cell body 1. Inhibition can be reliably prevented.

Furthermore, even if the resin film 8 is partially damaged and hangs down, the resin film 8 is between the holder 9 and the manifolds 3, 4, 6, 7, and prevents gas flow to the battery body 1 from being obstructed. This can be reliably prevented.

From the above, peeling of the Teflon coating on conventionally used manifolds easily occurs under the operating conditions of fuel cells, resulting in a situation where plant operation is stopped to prevent cell damage. According to this, all the problems can be solved.

That is, Teflon is currently the most effective material for preventing metal corrosion under materially severe conditions such as a fuel cell operating temperature of 200° C. and a phosphoric acid atmosphere. However, as mentioned above, Teflon does not have an adhesive brimer that can be used at 200℃, and its coefficient of linear expansion is an order of magnitude different from that of steel, making it susceptible to temperature changes due to temperature rises and falls during plant startup and shutdown.
Therefore, it is easy to peel off, and due to the gas permeability of Teflon itself, the gas stagnant between the manifold and the ring may expand when the manifold pressure is lowered when the plant is stopped, resulting in peeling. This peeled off coating obstructs gas flow and causes polarity reversal of the battery, and if operation continues, the battery will be damaged and become unusable. In the conventional manifold Teflon coating method, such problems are likely to occur due to repeated startup and shutdown of the plant. In this regard, the method used in this example uses an extremely simple method to reliably prevent gas flow obstruction caused by the release coating, enabling continuous operation of the fuel cell over a long period of time, and improving reliability as a power generation facility. This will make a major contribution.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and for example, as the resin film holder 9, as shown in a perspective view in FIG. Also, as in the case of FIG. 2, leaning against the battery body 1 can be prevented. At the same time, it is also possible to prevent obstruction of gas flow due to peeling of the resin film at the upper and lower bottom portions of the manifold 3°4.6.7.

[Effect of the Invention 1] As explained above, according to the present invention, the inner surface of the manifold is wrapped in a heat-resistant and chemical-resistant resin film, and a holder for the resin film is placed between the resin film and the groove-top battery body. Because it is configured to be attached, even if the resin film peels off, it prevents the battery from leaning against or sagging, ensuring a uniform flow of gas, and ensuring continuous operation over long periods of time, ensuring reliability as a power generation facility. A fuel cell that can improve performance can be provided.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing one embodiment of the present invention.
A-A' sectional view in the figure, Figure 3 is a sectional view of the holder, Figure 4 is a sectional view of the holder,
5 is a perspective view showing another embodiment of the present invention; FIG. 6 is an exploded perspective view showing a conventional fuel cell; FIG. The figure is a cross-sectional view showing the state of the battery when the resin film is peeled off. DESCRIPTION OF SYMBOLS 1...Battery main body, 2...Reinforcing material, 3...Fuel inlet manifold, 4...Fuel outlet manifold, 5...
・Sealing material, 6...Air inlet manifold, 7...
Air outlet manifold, 8... Resin film, 9...
- Holding body, 10...resin tube, 11...metal rod. Applicant's agent Patent attorney Takehiko Suzue 13 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (7)

[Claims] (1) A fuel cell body is formed by stacking a plurality of unit cells in which a matrix that holds an electrolyte is arranged between a pair of gas diffusion electrodes that have a fuel flow path and an oxidant flow path through which fuel and oxidizer flow. In a fuel cell configured by arranging a manifold on a side surface of the fuel cell main body for supplying and discharging fuel and oxidizer to and from the gas diffusion electrode, respectively, and sealing between the manifold and the fuel cell main body, A fuel cell characterized in that the inner surface of the manifold is wrapped in a heat-resistant and chemical-resistant resin film, and a holder for the resin film is attached between the resin film and the fuel cell main body. (2) In what is stated in claim (1),
The manifold is provided with a pair of manifolds for supplying and discharging fuel through gas supply and discharge pipes on one side facing the fuel cell main body, and a pair of manifolds for supplying and discharging fuel through gas supply and discharge pipes on the other side perpendicular to this. A fuel cell characterized by being equipped with a manifold. (3) In what is stated in claim (1),
A fuel cell characterized in that the resin film is a fluororesin. (4) In what is stated in claim (1),
A fuel cell characterized in that a resin film is coated on a manifold. (5) In what is stated in claim (1),
A fuel cell characterized in that the resin film is pre-formed to match the inner surface of the manifold. (6) In what is stated in claim (1),
A fuel cell characterized in that the resin film holder is a metal rod encapsulated in a fluororesin tube. (7) In what is stated in claim (1),
A fuel cell characterized in that the resin film holder is a metal mesh encapsulated in a fluororesin film.